How to Avoid Digging Up a Sprinkler System

Read over any plans or drawings given to you by the sprinkler company that installed your system, which may be located on or near the controller box in your garage or house. If you don't see any drawings, contact the installation company -- also indicated on the box -- and ask whether they have any information on file. If you can't find the schematics that indicate where the lines and sprinkler heads are, it will be more of a guessing game to find them, and you'll have to take extra caution.

Make a sketch of your yard, using graph paper to draw it of the correct proportions. The graph paper will have small squares, each of which will indicate 1 square foot. Look for the backflow device on the outside of your house or garage, which looks like a pipe with a faucet-like handle on it. Draw it and other landmarks on your sketch.

Turn on the sprinklers and observe where you see the water coming out from the heads. Measure the distance of a landmark you've already added to your sketch so you can plot out the sprinkler heads accurately and draw the heads on your paper in their corresponding locations. From the location of the heads, you should be able to determine where the water lines are. If the heads pop out in a line formation, you can assume there's a water line running between each head.

Draw a line on the sketch between each sprinkler head. Look for the nearest sprinkler head to the backflow handle, and draw a line from the head to the backflow handle. While you may not draw it in exactly the right location, you'll at least get a rough idea of where the lines may be located.

Wet down the area where you plan to dig with a garden hose, to make it easier to dig in that area. This will discourage you from using excess pressure when digging.

Use a shovel to dig down as far as 6 inches along the areas you've marked as probable water line locations, avoiding the sprinkler head areas for now. Sprinkler lines are typically 8 to 12 inches deep, so for the top 6 inches of earth you won't have to worry too much about damaging your sprinkler lines. Use a trowel to remove the soil around sprinkler heads.

Use extreme caution at 6 inches below the soil line, scraping the layers of soil rather than digging. Look for any sprinkler lines, which are typically made from hard plastic.